Energy from fluid flow is used in many applications. For example, jet ejectors, such as steam ejectors, are used as compressors in evaporators. And propulsive jets are used in applications such as jet aircraft, watercraft, missiles, and rockets. As with most mechanical apparatuses that transfer input energy to a useful output energy, efficiency is important; therefore, manufacturers of jet ejectors and propulsive jets are continually searching for more and better techniques to increase efficiency.